Synesthesia is a disorder resulting in the sufferer experiencing an alternate sense as a result of the first sense. And speaking of sense, that sentence might not have made any to you. Let's break it down someone with Synesthesia might say:
“Your shirt is too loud, put down the volume”
“I see the letter 5 as green with striped”
“Dude the chick’s number taste like strawberries”
Synesthesia is (as you probably guessed) basically results from your neural "wires" getting crossed. You can see it as your worlds are colliding, and it isn’t necessarily a bad thing, you can see it as having a deeper understanding of art and having a different perception that no one else may have. As of now, the greatest evidence we have of this “union of senses” is that of genetic predisposition. Although very little is known about this disorder, it is prevalent as every 1 in 23 persons can have some trait of it. However you don’t have to be born with it to experience it you can be under the influence of the psychedelic drugs, have a stroke, have an epilepsy to experience this!
Some of the famous entertainers have synesthesia (is it cheating?!) such as: Marilyn Monroe, John Mayer, Marina Diamandis, Vladimir Nabokov, and so much more!
There are various forms of Synethesia like:
Grapheme to color synesthesia: this is when individual letters of the alphabet and/or number are a different colors.
Spatial sequence Synesthesia: this is when people tend to see all numerical sequences they come across as points in space. As in 1 can be further away from 2 than 3 is.
Sound to color synesthesia: what you hear has a color; like a dog’s barking can have a shade of green)
This video is about a guy with synesthesia and how he views his world, it is interesting to see and hear how his world is and absolutely fascinating